The surface of the Dead Sea is over 1,300 feet below sea level. The very bottom of
the sea, in the deepest part, is over 2,300 feet below sea level.
The Dead Sea has some of the most saline water on earth; as much
as 35% of the water is dissolved salts! That's almost six times
as salty as the ocean! The Dead Sea is completely landlocked
and it gets saltier with increasing depth. Near the bottom of the Dead Sea the salt concentrations are so saturated that salt crystals precipitate out of the water and settle to the sea floor. The surface, fed by the
River Jordan, is the least saline. Down to about 130 feet (40 meters),
the seawater comprises about 300 grams of salt per kilogram of seawater.
That's about ten times the salinity of the oceans. Below 300 feet,
though, the sea has 332 grams of salt per kilogram of seawater and
is saturated, which means the water can't contain any more dissolved salts.

There are no fish or any kind of swimming, squirming creatures living in or near the water. There are, however, several types of bacteria and one type of algea that have adapted to harsh life in the waters of the Dead Sea. What you'll see on the shores of the Sea is white, crystals of salt covering everything. And this is no ordinary table salt, either. The salts found in the Dead Sea are mineral salts, just like you find in the oceans of the world, only in extreme concentrations. The water in the Dead Sea is deadly to most living things. Fish accidentally swimming into the waters from one of the several freshwater streams that feed the Sea are killed instantly, their bodies quickly coated with a preserving layer of salt crystals and then tossed onto shore by the wind and waves.

The
man at right is actually floating in the Dead Sea.

"But hey,
I thought you said the Dead Sea was deadly?"

Not to us. Humans
are remarkably adaptable. We can swim in the Dead Sea, just like
we can swim in the ocean. Well, people don't really "swim" in the
Dead Sea - they just "hang out". That's what's so cool about the
Dead Sea. Because of the extremely high concentration of dissolved
mineral salts in the water its density is way more than that of plain fresh water. What this means
is our bodies are more buoyant in the Dead Sea - so you bob like a cork. In fact, people are so
buoyant in this water, it makes it kinda tough to actually swim.
Most people like to just kick back in the water and read. It almost
looks as though this guy is sitting on an air mattress that has
sunk below the surface, but he's not. He's really just floating,
without having to hold is feet in that position! If you think this
is easy, try floating like this in a freshwater swimming pool.

What Caused the Dead Sea to Form?

This lesson
takes us back to the subject of plate tectonics. In this part of the
world there is a rift forming where two crustal plates are spreading apart.The East Rift Valley runs through most of Africa, starting north of the Dead Sea and running south along the
eastern side of the continent. The Dead Sea is located right along the
Rift Valley where the earth's crust is being stretched thin. To get an idea of how this "crustal spreading"
thing works, take a bar of taffy, or taffy-like candy and try to pull
it apart. You'll see where the candy starts to come apart it gets
really thin just before it breaks. That's what is happening to the
earth's crust in the Rift Valley. Where the earth's crust gets thin
that part of the surface sinks downward. The Dead Sea is still continues to sink lower, even today.
Scientists estimate that the Dead Sea lowers by as much as 13 inches
per year. On a geologic time scale that's incredibly fast!

Why is the Dead Sea so Salty?

We talked about how the surface
of the Dead Sea got down so low in elevation, but why is it so salty? All
roads lead to the Sea when it comes to the rivers in the area. The
Dead Sea is continually fed water from the rivers and streams coming
down off the mountains that surround it. But the kicker is this....no
rivers drain out of the Dead Sea. The only way water gets out of the
Sea is through evaporation. And boy does it evaporate! This part of
the world get plenty hot. When the water
evaporates, it leaves behind all the dissolved minerals in the Sea,
just making it saltier. In fact, it's through the dual action of;
1) continuing evaporation and 2) minerals salts carried into the Dead Sea
from the local rivers, that makes the Sea so salty. The fact that
the water doesn't escape the Sea just traps the salts within its shores.